Retirement tax questions

AmyC,

Thank you for the response.  I am familiar with the treaty, what i am trying to determine if

1. What document the UK will send me so I know how much pension I need to report?

2. When do they issue the document?

I would be surprised if I just add up the deposits in my bank account for 2020 to find the amount as I am assuming I will need to provide more information when I report my UK pension. 

Thanks,